Method of detecting radioactive substance

Abstract

A method of detecting radioactive substance in a liquid sample which comprises steps of: (1) supplying a radiation-measuring instrument containing a stimulable phosphor with the liquid sample continuously or intermittently; (2) keeping said measuring instrument in contact with the liquid sample for a given period of time to cause the instrument to absorb at least a portion of radiation energy emitted by the radioactive substance in said liquid sample; and (3) irradiating said measuring instrument with an electromagnetic wave to release the radiation energy stored in the instrument as stimulated emission, and photoelectrically detecting the stimulated emission to measure radioactivity of said liquid sample sequentially. The method is particularly useful when employed in conjunction with liquid chromatography.

I claim: 
     
       1. A method of detecting radioactive substance in a liquid sample which comprises the steps of: (1) supplying a radiation-measuring instrument having a stimulable phosphor covered with a polymer material with the liquid sample continuously or intermittently;   (2) keeping said measuring instrument in contact with the liquid sample for a given period of time to cause the instrument to absorb at least a portion of radiation energy emitted by the radioactive substance in said liquid sample; and   (3) irradiating said measuring instrument with an electromagnetic wave to release the radiation energy stored in the instrument as stimulated emission, and photoelectrically detecting the stimulated emission to measure radioactivity of said liquid sample sequentially.   
     
     
       2. The method of detecting radioactive substance as claimed in claim 1, wherein the liquid sample is a liquid containing a radioactive substance and being treated by liquid chromatography. 
     
     
       3. The method of detecting radioactive substance as claimed in claim 1, wherein the content of the radioactive substance in the liquid sample is measured. 
     
     
       4. The method of detecting radioactive substance as claimed in claim 1, wherein the stimulable phosphor is a divalent europium activated alkaline earth metal fluorohalide phosphor. 
     
     
       5. The method of detecting radioactive substance as claimed in claim 1, wherein the stimulable phosphor is a rare earth element activated rare earth oxyhalide phosphor. 
     
     
       6. A method of detecting radioactive substance in a liquid sample treated in liquid chromatography which comprises steps of: (1) sequentially setting a plurality of measuring containers having a stimulable phosphor covered with a polymer material under a sample supplier containing a liquid sample, and supplying said liquid sample continuously or intermittently into said measuring containers from the sample supplier;   (2) keeping each of said plurality of measuring containers in contact with the liquid sample for a given period of time to cause the container to absorb at least a portion of radiation energy emitted by the radioactive substance in said liquid sample; and   (3) irradiating each of said plurality of measuring containers with an electromagnetic wave to release the radiation energy stored in the container as stimulated emission, and photoelectrically detecting the stimulated emission to measure radioactivity of said liquid sample sequentially.   
     
     
       7. The method of detecting radioactive substance as claimed in claim 6, wherein the measuring container has a built-in stimulable phosphor being dispersed in a binder. 
     
     
       8. The method of detecting radioactive substance as claimed in claim 6, wherein the measuring container is a plastic container with a built-in stimulable phosphor. 
     
     
       9. The method of detecting radioactive substance as claimed in claim 6, wherein the measuring container is a glass or quartz container with a built-in stimulable phosphor. 
     
     
       10. The method of detecting radioactive substance as claimed in claim 6, wherein the stimulable phosphor is a divalent europium activated alkaline earth metal fluorohalide phosphor. 
     
     
       11. The method of detecting radioactive substance as claimed in claim 6, wherein the stimulable phosphor is a rare earth element activated rare earth oxyhalide phosphor. 
     
     
       12. A method of detecting radioactive substance in a liquid sample treated in liquid chromatography which comprises steps of: (1) moving a continuous-length measuring instrument having a stimulable phosphor covered with a polymer material along the lengthwise direction under a sample supplier containing a liquid sample, and supplying said liquid sample continuously or intermittently onto said measuring instrument from the sample supplier;   (2) keeping said measuring instrument in contact with the liquid sample for a given period of time to cause the instrument to absorb at least a portion of radiation energy emitted by the radioactive substance in said liquid sample; and   (3) irradiating said measuring instrument with an electromagnetic wave to release the radiation energy stored in the instrument as stimulated emission, and photoelectrically detecting the stimulated emission to measure radioactivity of said liquid sample sequentially.   
     
     
       13. The method of detecting radioactive substance as claimed in claim 12, wherein the continuous-length measuring instrument is a plastic tape containing a stimulable phosphor therein. 
     
     
       14. The method of detecting radioactive substance as claimed in claim 12, wherein the continuous-length measuring instrument has a liquid-adsorbing ability. 
     
     
       15. The method of detecting radioactive substance as claimed in claim 12, wherein the continuous-length measuring instrument is a yarn or fabric made of a plastic fiber containing a stimulable phosphor therein. 
     
     
       16. The method of detecting radioactive substance as claimed in claim 12, wherein the continuous-length measuring instrument is a yarn or fabric made of a glass fiber containing a stimulable phosphor therein. 
     
     
       17. The method of detecting radioactive substance as claimed in claim 12, wherein the stimulable phosphor is a divalent europium activated alkaline earth metal fluorohalide phosphor. 
     
     
       18. The method of detecting radioactive substance as claimed in claim 12, wherein the stimulable phosphor is a rare earth element activated rare earth oxyhalide phosphor. 
     
     
       19. A method of detecting radioactive substance in a liquid sample treated in liquid chromatography which comprises steps of: (1) moving a sheet-form measuring instrument in the direction along the sheet-plane under a sample supplier containing a liquid sample, said measuring instrument comprising a stimulable phosphor member containing a stimulable phosphor therein, a transparent polymer film, and a liquid-retaining member provided in order, and supplying said liquid-retaining member of the measuring instrument from the sample supplier;   (2) keeping said liquid-retaining member of the measuring instrument in contact with the liquid sample for a given period of time to cause the stimulable phosphor member thereof to absorb at least a portion of radiation energy emitted by the radioactive substance in said liquid sample; and   (3) irradiating said measuring instrument with an electromagnetic wave to release the radiation energy stored in the instrument as stimulated emission, and photoelectrically detecting the stimulated emission to measure radioactivity of said liquid sample sequentially.   
     
     
       20. The method of detecting radioactive substance as claimed in claim 19, wherein the sheet-form measuring instrument is in a quadrangular form, and in the step (1), the movement of said measuring instrument is done in such a manner that the instrument moves by mutual repetition of going to and from along one side of the quadrangular in conjunction with a shift in the direction perpendicular being arranged therebetween. 
     
     
       21. The method of detecting radioactive substance as claimed in claim 19, wherein the liquid-retaining member of the sheet-form measuring instrument has a porous structure. 
     
     
       22. The method of detecting radioactive substance as claimed in claim 19, wherein the stimulable phosphor member of the sheet-form measuring instrument comprises a binder and a stimulable phosphor dispersed therein. 
     
     
       23. The method of detecting radioactive substance as claimed in claim 19, wherein the stimulable phosphor is a divalent europium activated alkaline earth metal fluorohalide phosphor. 
     
     
       24. The method of detecting radioactive substance as claimed in claim 19, wherein the stimulable phosphor is a rare earth element activated rare earth oxyhalide phosphor. 
     
     
       25. A method of detecting radioactive substance in a liquid sample treated in liquid chromatography which comprises steps of: (1) moving a sheet-form liquid-retaining member in the direction along the sheet-plane under a sample supplier containing a liquid sample, and supplying said liquid sample continuously or intermittently onto said liquid-retaining member from the sample supplier;   (2) placing said liquid-retaining member carrying the liquid sample on a sheet-form stimulable phosphor member having a stimulable phosphor covered with a polymer material for a given period of time to cause the stimulable phosphor member to absorb at least a portion of radiation energy emitted by the radioactive substance in said liquid sample; and   (3) irradiating said stimulable phosphor member with an electromagnetic wave to release the radiation energy stored in the stimulable phosphor member as stimulated emission, and photoelectrically detecting the stimulated emission to measure radioactivity of said liquid sample sequentially.   
     
     
       26. The method of detecting radioactive substance as claimed in claim 25, wherein the liquid-retaining member is in a quadrangular form, and in the step (1), the movement of said liquid-retaining member is done in such a manner that the member moves by mutual repetition of going to and from along one side of the quadrangle in conjunction with a shift in the direction perpendicular being arranged therebetween. 
     
     
       27. The method of detecting radioactive substance as claimed in claim 25, wherein the liquid-retaining member has a porous structure. 
     
     
       28. The method of detecting radioactive substance as claimed in claim 25, wherein the stimulable phosphor sheet comprises a binder and a stimulable phosphor dispersed therein. 
     
     
       29. The method of detecting radioactive substance as claimed in claim 25, wherein the stimulable phosphor is a divalent europium activated alkaline earth metal fluorohalide phosphor. 
     
     
       30. The method of detecting radioactive substance as claimed in claim 25, wherein the stimulable phosphor is a rare earth element activated rare earth oxyhalide phosphor.